Scale experiment for Indirect Bridge Monitoring

James Garrett, Civil and Environmental Engineering

Structural Health Monitoring (SHM) is a major concern for Bridge Authorities. In the aftermath of the 2007 I-35W Mississippi River bridge collapse in Minneapolis, a 2010 U.S. Department of Transportation report rated 26% of the country's nearly 600,000 bridges either structurally deficient or "functionally obsolete". Since then, the search for reliable structural health monitoring (SHM) technologies able to prevent catastrophic failures or to flag early signs of early deterioration became a top priority.

To date, besides mandatory visual inspection, the SHM of bridges is conducted using direct approaches where sensors are deployed in the structure and measurements are streamed to a centralized unit for data cleansing, feature extraction and classification, to provide diagnostics. This approach faces several practical problems and great direct and maintenance costs

We have been working on a paradigm shifting approach for indirect monitoring. This approach has the advantages of decentralizing the monitoring apparatus to fleets of vehicles that can continuously store or send data. The objective is cost-effective and sustainable assessments of a large population of bridges.

Figure 1: Laboratory experiment scheme, figure provided by professor KIM

Objective: Obtain scale experiment vehicle-bridge interaction data to evaluate detection capability of signal processing algorithm

Experiment description:

The experiment considers an instrumented vehicle with accelerometers running over a simply supported bridge structure. The vehicle should run under controlled velocity range and at a fixed velocity while crossing the main bridge span. At least three vehicle types will be studied by modifying the vehicle’s fundamental frequency through a change in the mass and the suspension stiffness. Several reversible damage scenarios will be inflicted into the structure. Some of these scenarios consider inclusion of damping, crack areas, fixed support conditions, thermal changes. A roadway roughness profile should be included in the experiment.

If interested, please contact Professors Jim Garrett (garrett@cmu.edu) and
Jacobo Bielak in CEE to get more details.